Stuffing of chrome-tanned heavy leather



Patented Aug. 16, 1927.

UNITED STATES ROBERT HOWSON PICKARD, DOROTHY JOBD OF LONDON,

AN LLOYD, AND ALBERT EDWARD cannon,

ENGLAND.

STUFFING OF CHROME-TANNED HEAVY LEATHER.

No Drawing; Application filed August 22, 1925, Seri This invention has reference to improvements in and relating to the stuffing of chrome tanned heavy leather. 7

The stufling of chrome tanned heavy leather has been practised for many years but as heretofore carried out the leather loses considerably in volume, that is to say the finished or stufied leather has a much or at any rate what is considered a substantially less volume than the leather had when in the wet blue condition.

This loss of volume, due to the immersion drated leather in the mo ing material whilst the in a shrunken condition.

The main object of our invention is to obviate this defect and to this end an important feature of our invention consists in steeping chrome tanned heavy leather in a bath or successive baths of acetone until the water content of the leather is reduced to from 14 to (according to the character of the leather) removing the acetone from the leather, and then steeping or otherwise treating the leather in or with any usual stuffing material or mixture.

By the treatment described the finished product is a stuffed chrome leatherhaving the same or to all intents the same volume as the leather had when in the wet blue state.

It is not possible to state in precise terms how long the treatment should be continued as this will depend upon various considerations and circumstances such as the thickness of the leather; the character of the leather; the condition of the acetone employed, that is to say whether it contains any and, if so, how much, water; and the temperature at which the treatment is carried out.

It is advisable therefore to take certainprecautions.

For instance, a sample piece or cutting of the leather under treatment may be removed and dried (this drying may conceivably be effected by heating the sample to a temperature of about 135 Fah., or 57 Cent.) and if said sample piece when immersed in water immediately wets back the treatment is complete and the leather must now be removed, drained, and its acetone content evaporated, for instance by exposure to a current of warm air.

As a result of many tests we find that the it is .well known, it t the dried or dehylten or liquid stufffibrous structure is al No. 51,875, and in Great Britain August 27, 1924.

average or normal water content of chrome leather is about 14 to 20% (according to the character of the leather) and therefore by removing a sample piece of the leather after the acetone has been evaporated off, as described, and weighing it, and then drying it (say at 220 Fah.-104 Cent.) and weighing again, it is possible to ascertain if the treatment has been properly carried out.

As a result of tests we find that if the leather in the wet blue state is immersed in acetone of full strength the acetone treatment willbe complete when the leather is in equilibrium with a water and acetone mixture of gravity 0.810. When this occurs the leather or acetone should at once be removed and the acetone content of the leather driven off as described.

In order to expedite the evaporation off of the acetone we may first subject the water and acetone saturated leather to the action of warm dry air and when the bulk of the acetone has been removed we may supply moist air.

If the workman has allowed the process to be continued so long that the fibrous structure has shrunk he must at once subject the leather to the action of moist air.

The air (or may be inert gas) whereby the acetone is evaporated ofl". may with advan tage be at a temperature of about 135 Fah. (57 Cent).

The leather thus prepared and consequently of full volume is then immersed in a bath of or treated with stuffing material or mixture in the usual way.

Of course the evaporation of the acetone content of the leather will in practice be carried out so that the acetone is recovered and may again be used.

Claims:

1. The manufacture of stuifed leather by steeping chrome tanned leather in the wet blue state in a bath of acetone until the water content of the leather is reduced to from 14 to 20%; removing theacetone from the leather, and then treating the latter with a suitable stufling material.

2. In the manufacture of stufled chrome leather according to claim 1, steeping the leather in the wet blue state in actone until a sample cutting thereof dried at approximately 135 Fah. (57 Cent.) will wet back in water, and then removing the acetone content of the leather.

3. In the manufacture of stufii'ecl chrome leather according to claim 1, steeping the leather in the Wet blue state in acetone until the leather is in equilibrium With a Water and acetone mixture of gravity 0810.

i. The manufacture of stuffed leather according to claim 1 by steeping chrome tanned leather in the Wet blue state in acetone of full strength, removing the acetone ilromthe-leather by subjectingit to-the 210- tion of airwhich may be mois-tat a tem perature of about 135 Fah. (57 Cent), and

:then: treatingit with *a suitable stulfmg; material.

Certificate of Correction.- Patent No. 1,638,877. Granted August 16, 1927, to ROBERT HOWSON PIOKARD ET AL.

It is hereby certified that error appears in the printed specification of the abovenumbered patent requiring correction as follows: Page 1, line 106, for the Word actone read acetone; and that the said Letters Patent should he read With this (grrection therein that the same may conform to the record of the case in the Patent Signed and sealed this 4th day of October, A. D. 1927.

[SEAL.] M. J. MOORE Acting Umnmissz'on-er of Patents. 

